PERIOD PROTEIN IS NECESSARY FOR CIRCADIAN CONTROL OF EGG HATCHING BEHAVIOR IN THE SILKMOTH ANTHERAEA-PERNYI

We examined the molecular basis of the circadian control of egg hatchi ng behavior in the silkmoth Antheraea pernyi. Egg hatching is rhythmic ally gated, persists under constant darkness, and can be entrained by light by midembryogenesis. The time of appearance of photic entrainmen t by the silkmoth embryo coincides with the appearance of Period (PER) and Timeless (TIM) proteins in eight cells in embryonic brain. Althou gh daily rhythms in PER and/or TIM immunoreactivity in embryonic brain were not detected, a robust circadian oscillation of PER immunoreacti vity is present in the nuclei of midgut epithelium. per antisense olig odeoxynucleotide treatment of pharate larvae on the day before hatchin g consistently abolishes the circadian gate of egg hatching behavior. per antisense treatment also causes a dramatic decrease in PER immunor eactivity in newly hatched larvae. The results provide direct evidence that PER is a necessary element of a circadian system in the silkmoth .